Subject: Western Pacific: Synoptic Discussion For The Marianas

From: LDM Weather <[email-masked]>
Date: Wed, 22 Dec 2010 15:52:02 -0600

998 
FXPQ60 PGUM 222151
AFDPQ 

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE TIYAN GU
751 AM CHST THU DEC 23 2010

.SYNOPSIS...
PGUA WSR-88D SHOWS ALMOST NO SHOWERS IN THE MARIANAS WATERS. IR
SATELLITE SHOWS A FEW SHOWERS SOUTH OF GUAM MOVING FARTHER SOUTH.
TO THE NORTH SKIES ARE PARTLY CLOUDY WITH JUST ISOLATED SHOWERS...
A DRY SEASON TRADE-WIND PATTERN.

&&

.DISCUSSION...
ALLOWED FOR ISLAND EFFECT TO INCREASE CLOUD COVER AGAIN TODAY AND
MAINTAINED PARTLY SUNNY WORDING. AFTER THAT WINDS PICK UP A BIT SO
DECREASED CLOUDS THE NEXT COUPLE OF DAYS TO PARTLY CLOUDY WORDING.
OTHERWISE THE GENERAL PATTERN WAS WELL REPRESENTED IN THE GRIDS.
BOTH ECMWF-HIRES AND GFS40 MAINTAIN A WINTER TIME PATTERN OF NEAR
APPROACHES BY SHEAR LINES. NEED TO WAIT A FEW DAYS BEFORE WE TRY
TO DETERMINE WHICH ARE NEAR MISSES AND WHICH WILL ACTUALLY AFFECT
OUR WEATHER.

&&

.MARINE...
NORTHEAST SWELLS WILL MAINTAIN SEA AND SURF HEIGHTS AT A BIT BELOW
SMALL CRAFT AND HIGH SURF ADVISORY THRESHOLDS. THE SWELLS WILL
REMAIN NEAR THESE HEIGHTS SO AT THIS TIME NO ADVISORIES ARE
EXPECTED.

&&

.EASTERN MICRONESIA...
A PERSISTING SURFACE RIDGE SOUTHEAST OF A COLD FRONT NEAR WAKE 
ISLAND ALONG WITH A VERY DRY AIR MASS ALOFT WILL MAINTAIN FAIR 
WEATHER ACROSS THE ENTIRE REGION THRU FRIDAY. AS THE COLD FRONT 
SHIFTS TO THE EAST OF THE DATE LINE BY THE WEEKEND...IT WILL CAUSE 
THE SURFACE RIDGE TO LIFT NORTHWARD AND WEAKEN. THIS WILL FINALLY 
ALLOW A TRADE-WIND SURGE CURRENTLY EAST OF THE DATE LINE TO MIGRATE 
WESTWARD. INCREASING TRADE CONVERGENCE COULD INTRODUCE MORE SHOWER 
ACTIVITY FROM EAST TO WEST INTO NEXT WEEK.

A NORTHEAST SWELL WILL GRADUALLY RAISE SURF HEIGHTS ACROSS CHUUK AND 
POHNPEI BY FRIDAY AFTERNOON. THEN BUILDING TRADE-WIND SWELLS AND 
WIND WAVES WILL SPREAD SIMILAR SURF CONDITIONS INTO KOSRAE AND THE 
MARSHALLS OVER THE WEEKEND. THIS MIGHT PRODUCE A HIGH SURF EVENT ON 
KOSRAE BY SATURDAY...WHICH NEEDS TO BE MONITORED.

&&

.WESTERN MICRONESIA...
WITH THE AXIS OF A WEAK NEAR-EQUATORIAL TROUGH REMAINING SOUTH OF 
BOTH CHUUK AND YAP...DRY AIR AND CONVERGENT FLOW AT MID TO UPPER 
LEVELS WILL PROMOTE PLEASANT CONDITIONS AT CHUUK THRU SATURDAY AND 
FOR YAP INTO FRIDAY. UNDER THE INFLUENCE OF THE NEAR-EQUATORIAL 
TROUGH...KOROR WILL EXPERIENCE MORE PASSING SHOWERS THRU FRIDAY. 
THEN THE RETURN OF A MORE SEASONAL TRADE-WIND PATTERN FROM THE EAST 
WILL CAUSE THE NEAR-EQUATORIAL TROUGH TO RETREAT WESTWARD TOWARD THE
PHILIPPINES. GENTLE TRADES SHOULD PROVIDE A PERIOD OF PARTLY
CLOUDY SKIES OVER KOROR INTO THE WEEKEND. HOWEVER HEIGHTENING
TRADE CONVERGENCE IS GOING TO PUT AN END TO THE QUIET WEATHER ON
BOTH CHUUK AND YAP DURING THE WEEKEND.

&&

.GUM WATCHES/WARNINGS/ADVISORIES...
GU...NONE.
MARIANAS WATERS...NONE.
&&

$$

STANKO/CHAN

+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
To unsubscribe from WX-TROPL send e-mail to [email-masked] with
"unsub wx-tropl" in the body of your message. For help with WX-TROPL
write to [email-masked]. For more information on tropical weather products, see the NHC Homepage at http://www.nhc.noaa.gov.